(1) Field of the Invention
The present invention relates to the field of power management and conservation within a computer system.
(2) Prior Art
The importance of power management for computer systems is growing as computer systems become complex and the need to conserve power within the components of a computer system becomes more critical. This is particularly true regarding laptop and other portable or battery operated computer systems. Interest in power management continues to grow in the computer community for both battery-operated systems and AC-powered desktops (so-called "Green" "PCs"). By reducing power consumption, not only is battery lifetime prolonged, but energy is conserved and heat generation is reduced.
Heretofore, systems have been implemented for power management features for IBM compatible computer systems that utilize a BIOS (or Basic Input/Output System firmware) for controlling the computer components that are located within the "motherboard" of the computer system or components that are delivered to the end user with the motherboard. As is well known in the computer industry, the BIOS is able to place the computer components into several power reduction states (e.g., standby, suspend, etc.). While this is useful for controlling the power consumption of the motherboard components (and components shipped with the computer to the end user), what is needed is a system for controlling the power management and other related functions of the entire computer system including add-in cards (e.g., PCMCIA devices). PCMCIA is a well known standard interface for computer systems and peripherals. These add-in cards are added by the user after purchase and are typically not power managed by the system. The present invention offers the advantageous functionality for providing a uniform power management system for add-in cards of a computer system that greatly expands the power management capabilities of the BIOS.
An APM (Advanced Power Management) BIOS was introduced to facilitate power management within computer systems. While useful for certain systems, the APM BIOS utilizes very complex connections and most importantly no software component or device (aside from the APM BIOS) could initiate a power management event (such as a shut down request) without going through the APM BIOS. Further, since the APM BIOS power management is located within the firmware, power down events initiated by the APM BIOS are not always responded to well by application programs (e.g., time dependent programs) running on the computer when power down is implemented. Therefore, what is needed is a mechanism to facilitate the initiation of a power management event from a software component. What is needed is a system that allows and recognizes power management events that originate from a software component, such as an application program. The present invention provides such advantageous functionality.
Accordingly, it is an object of the present invention to provide a power management system and interface for a computer system that responds to and manages add-in devices that are integrated with the system by a user. Further it is an object of the present invention to provide such a system that is flexible and easily responds to new devices added to or removed from an existing system. It is also an object of the present invention to provide such a power management system with extremely flexible and programmable power management policies. It is another object of the present invention to provide a power management system capable of responding to a power management event originating from an application program. It is also an object of the present invention to remain backward compatible with the APM BIOS power management systems. These objects of the present invention and others not specifically recited herein will be become clear within further discussions to follow.